A second jet in the core of the blazar Markarian 501, about 460 million light-years away in Hercules, points to two supermassive black holes orbiting each other roughly every 121 days, only 250–540 times the Earth–Sun distance apart. The team led by Silke Britzen (Max Planck Institute for Radio Astronomy) used about 23 years of radio data; an alignment in June 2022 produced a ring-like feature read as an Einstein ring. Depending on their masses they could merge in as little as about 100 years. The paper is from April 2026; the second black hole is inferred, not imaged, and poses no danger.
121days: one orbit of the pair
250–540times the Earth–Sun distance apart
≈ 100years: earliest possible merger (mass-dependent)
Markarian 501 is a galaxy about 460 million light-years away in the constellation Hercules. It is a blazar: a supermassive black hole at its centre fires a jet of particles almost straight at us, which makes it one of the brightest sources of high-energy light in the sky. A team led by Silke Britzen of the Max Planck Institute for Radio Astronomy in Bonn has now found a second jet in its core.
Two jets mean two engines. The team concludes that the core holds two supermassive black holes, each with an estimated 100 million to 1 billion times the mass of the Sun, orbiting each other about every 121 days. They are only 250 to 540 times the Earth–Sun distance apart, a gap the size of a large planetary system. “We searched for it for so long,” Britzen said.
How do you find a black hole you cannot see?
Nobody can see the second black hole directly; even the Event Horizon Telescope, which photographed the black hole in M87, cannot separate the two. The evidence is in the jets. The team analysed about 23 years of radio observations and found the jet direction swinging in a regular rhythm, plus a second, fainter jet that only makes sense if a second black hole is launching it.
In June 2022 the two lined up as seen from Earth, and the radio data show a ring-shaped feature that the team interprets as an Einstein ring: the gravity of the front black hole bending the light of its partner’s jet. An alignment like that is a rare test of the model, and it fits.
GalaxyMarkarian 501 (Hercules)
Distance≈ 460 million light-years
Orbit≈ 121 days
Separation250–540 × Earth–Sun distance
Masses≈ 100 million–1 billion Suns each
PaperBritzen et al., MNRAS 2026
Two black holes, two jets, one rhythm
Original Astrometrik animation, simplified and not to scale. Left: two supermassive black holes orbit each other every ~121 days; each launches a jet, and the jets wobble with the orbit. Right: their separation (250–540 times the Earth–Sun distance) compared with Neptune’s orbit and Voyager 1, plus the gravitational-wave pitch that should rise as they spiral together.
A merger within a century?
Two black holes this close lose orbital energy to gravitational waves, ripples in space-time, and slowly spiral together. Depending on the true masses, the team estimates they could merge in as little as about 100 years, which is an eye-blink for galaxies. The waves from such heavy pairs are too slow for LIGO; they would show up in pulsar timing arrays, which watch dozens of millisecond pulsars for tiny shifts in their ticks.
Héctor Olivares of the University of Aveiro, a co-author, points to the signature to look for: as the two spiral in, the frequency of the waves should rise. Catching that rise for a known, named pair would be a first.
Honest caveats for the viral version
This is not brand-new: the study appeared in Monthly Notices of the Royal Astronomical Society and the Max Planck release came out in April 2026; it went viral again in October. The light we see left the galaxy about 460 million years ago, so any merger already happened, or not, long ago in its own time, and there is no danger to Earth at all.
The second black hole is inferred from the jets, not imaged, and the masses are a range, not a measurement. Other explanations for jet wobbles exist, such as a precessing single jet, but the second jet is hard to explain without a second engine. Future radio monitoring and pulsar timing data will test the claim.
Viral claims, checked
What posts say about Markarian 501, and what the study supports:
TrueAstronomers found a second jet in Markarian 501Yes, published in MNRAS (Britzen et al., 2026) from about 23 years of radio data.
PartlyTwo black holes caught orbiting each otherStrong evidence, not an image: the second black hole is inferred from the second jet and the jet’s regular wobble.
PartlyThey will collide within 100 years“As little as” about 100 years, and only if the masses are at the high end; it could take much longer.
PartlyA brand-new discoveryThe paper and the Max Planck release came out in April 2026; the story went viral again in October.
FalseThe merger could be dangerous for EarthNo. The galaxy is about 460 million light-years away; its gravitational waves would be measurable only with very sensitive instruments.
From radio data to viral post
≈ 2000–2023about 23 years of radio observations of the core
June 2022the two line up: a ring-like feature, read as an Einstein ring
April 2026paper in MNRAS and Max Planck press release
October 2026the story goes viral again
Find Hercules tonight
Markarian 501 is far too faint to see, but its home constellation Hercules sets in the west in the early evening at this time of year. Tap the button and the camera view points you there.
A second jet in the core of the blazar Markarian 501, which points to two supermassive black holes orbiting each other about every 121 days, 250 to 540 times the Earth–Sun distance apart (Britzen et al., MNRAS 2026).
When will the black holes in Markarian 501 merge?
Depending on their masses, the team estimates they could merge in as little as about 100 years. Because the galaxy is about 460 million light-years away, we would see it only that long after it happens.
Is the black hole pair dangerous to Earth?
No. It is about 460 million light-years away. Even its gravitational waves would be far too weak to affect anything here; they can only be detected with very sensitive instruments.
Has anyone seen the second black hole?
Not directly. No telescope can separate the two. The second black hole is inferred from a second jet, a regular wobble in 23 years of radio data and a ring-like feature seen when the two lined up in June 2022.
Sources and calculation
Sources: S. Britzen et al., “Detection of a second jet within the nuclear core of Mrk 501”, Monthly Notices of the Royal Astronomical Society 548(4), 2026, DOI 10.1093/mnras/stag291; Max Planck Institute for Radio Astronomy press release (April 2026); ScienceDaily (16 October 2026). Kepler’s law with a 121-day orbit and 250–540 au gives a total mass of roughly 140 million to 1.4 billion Suns, consistent with the reported range.
Positions and times were recalculated with Astronomy Engine, the sky-calculation library Astrometrik uses; times for Vienna and Istanbul are local time. The artwork on this page was drawn by Astrometrik.